Impulse transmitter for electric signaling devices



April 17, 1951 J. A. SPENCER EI'AL IMPULSE TRANSMITTER FOR ELECTRIC SIGNALING DEVICES 2 Sheets-Shet 1 Filed Jan. 28, 1948 mvzmonsc AMES A. SPEN eoumwuofiv AL 7% AT ORNEY April 1951 J. A. SPENCER ET AL 2,549,023

IMPULSE TRANSMITTER FOR ELECTRIC SIGNALING DEVICES Filed Jan. 28, 1948 2 Sheets-Sheet 2 ONECYCLEOF commmme 50 /20 UNIT UN 5 HEJL'I'HW'CRS ME A. SPENCER Q L NHARD FREINHOILD {ATTORNEY Patented Apr. 17, 1951 STATES iiRA'TENT OFFICE IMPULSE TRANSMITTER FOR ELECTRIC SIGNALING DEVICES James A. "Spencer, Teaneck, N. J., and Leonhard F. Reinhold, Great Kills, N. Y., assignors to "Radio Corporation of America, a corporation of Delaware Application January 28, 1948, Serial No. 4,866

8 Claims. (Cl. 178-79) The present invention relates to transmitter arrangements for telegraph systems utilizing step by step records, wherein a distinctive number of :equal length marking and spacing impulses are marking and spacing signal elements for controlling step by step recorders.

Another object of the present invention is the provision of a keyboard transmitter for operation with step by step printing telegraph systems.

An example of the present invention includes a keying arrangement for generating variable length trains of signal impulses in the form of current reversals. Said signal trains are intended for controlling stepby step printers. The keying arrangement includes a keyboard having one key for each character. The keys are mounted on mechanically interlocking push rodsoperating in a framework which also carries a series of hell cranks and levers, one each for each character key. A counting mechanism and control bail are mounted transversely beneath the lever assembly for controlling the rotation of a single cycle commutator. The single cycle commutator is adapted to be connected to the armature shaft of a continuously rotating electric motor through a toothed clutch cooperating with the transverse bail. The operation of any of the keys on the keyboard initiates the rotation of the commutator for sending out a train of signal elements. The number of elements in the train is characteristic of the character-on the key. A mechanism is provided for counting the number of signal elements generated and when the correct number is reachedfor the particular character selected, the commutator is disconnected from the source of power, a spacing impulse of extraordinary length is transmitted, and the keyboard and counting mechanism are returned to its normal position for the selection of another character.

The present invention will be more fully under* stood by reference to the following detailed description whichis accompanied by a drawing, in which:

Fig. 1 illustrates in fragmentary perspective the essential parts of a transmitter employing an embodiment of the present invention;

' Fig. 2 illustrates inv enlarged detail a portion of the structure of Fig. 1;

Fig. 3 illustrates a portion of the locking mechanism for the keyboard of Fig. 1;

Fig. l is a cross-section of the key locking mechanism of the keyboard of Fig.1;

Fig. dis a circuit diagram of the relays and contactors of Fig. 1; and

Fig.6 illustrates the form of the signal trains transmittedby the transmitter of Fig. 1.

Fig. 1 shows a-keyboard it] including a plurality of key strips l4 each having a numberof keys. ll

arranged thereon, one key for each character to be represented by transmitted signal trains. The

general arrangement of the keys on the-keyboard preferably follows that of the keys on a conventional typewriter. Each key H is mounted on a pushrod l2 passing through key stripl l and guidemember I5. Each bank of keys has associated therewith-a locking vane i6 pivoted along its lower edge to frame member I! and urged toward the push rods [2 of that bank of keys by return springs l8 (seealsoFigA). If any selected key I! is pressed, its push rod I2 is moved downwardly. The associated hinged locking vane I6 is forced outwardly by roller 2| carried: on push rod l2, thus-releasing any previously operated When the selected key I I reaches the bottom of its travel, roller 2| (shown in Fig. 4) enters a locking aperture or notch20 invane l6 and is mechanically locked in its selected position.

Associated with each push rod I2 is the return spring l8 acting to return the key to its unoperatedposition upon release of the locking mechanism. As each key is operated, the lower end ofits associated push rod I'Z moves downward-1y against the sloped nose of anassociated bell crank 22 pivoted on shaft23. The pressure of the push rod l2 against the sloped nose of the bell crank 22 causesthe bell-crank-to rotate in a counterclockwise direction. Thus the selector lever 24, pivoted to the lower end of bell crank 22, is moved in the direction indicated by arrow A. The selectorlevers-24 areeach provided on their lower edges with notches-25 and 26. These notches, when no keys are depressed'are in alignment with one another in all of the selector levers 24; All of thenotches 25-are (whenever the levers 24 occupy an unselected position) in direct alignment with the path along which inclined plane 32 on carriage 30 isadapted to move. When one of the levers 24 is selected, edge 3| on lever 24 is moved into the path-of the carriage 35) so that as the carriage 31] is moved in a direction from right to left the inclined plane 32 therein tendsto urge the selected lever '24 upwardly.

Notches26, in all of the selector levers, arein alignment when no selector lever24 is actuated. :An operatin bail 35 occupies the aligned notches. The bail 35 is urged toward the left hand edge of notches 26 by a spring36. It will be noted that whenever any one of theselector leversM is moved in the direction of arrow 3 A, bail 35 is rotated in a clockwise direction about teeth on rack 55.

8 1| open and 16 and 12 close.

on clutch member 4| is thereby released freeing clutch member 4| and allowing it to shift axially toengage with clutch member 42. Clutch member 42 is carried on a continuously rotating shaft 44 driven by an electric motor.

type having a conducting rim 56 over half of its 1 circumference insulatingly secured thereto. Brushes 5| and 52 are so placed as to engage the side of the commutator and the conducting rim 56 as they rotate. It will be seen that as commutator 48 is rotated brushes 5| and 52 are connected together through rim 56 for half of the period of revolution of shaft 46 thus generating one square wave cycle for each revolution of shaft 46, as shown in Fig. 6. Furthermore, as shaft 46 rotates, eccentric 41 imparts a reciprocating motion through shoe 53 and lever 54 to a ratchet rack 55. Ratchet rack 55 runs parallelto a guide bar 51 carrying carriage 36. Carriage 36 carries a pawl 58 which is adapted to engage the Carriage36 is further provided with a holding pawl 66 engaging in the teeth of a stationary rack 6|. Thus as shaft 41 completes one revolution, ecentric 41 completes one recipro cation of rack 55, advancing carriage 36 one step on the stationary rack 6|.

Now since the slots 25 on unactuated selector levers 24 are all in alignment with the nose on carriage 36, the carriage 36 passes them freely without affecting them. As it reaches the first actuated selector lever 24, the inclined ramp 32 engages the edge 3| on selector lever 5 causing that lever to move upwardly and disengage ball 35 from notch 26. The spring 36 is thus permitted to rotate the bail 35 in a counter-clockwise direction. Clutch lever 46 re-engages the cam face 39 on clutch member4| moving it axially away from the driving member 42, thus stopping shaft 46 from rotating. Since the commutator 48 and the rack 55 each complete one cyclic operation with each rotation of shaft 46, the movement of carriage 36 provides a means for counting the number of marking and spacing impulses transmitted by commutator 56.

The functioning of the electrical control circuits will now be described with reference to Figs. 1, 2, 3 and 5. Prior to initiating transmission, contacts 16 and 1| are closed and contacts 16 and 12 are open. Contacts 13 and 14 are open, as are contacts 15 and 16. When clutch 4| is released by bail 35, contacts 16 and 12 are closed by member 38, thus connecting a source of potential to charge a condenser 18 and contacts 16 and 12 are opened. Immediately when the carriage 36 begins to advance, contacts 15 and 16 are permitted to close. This connects a source of potential to the holding leaf contact spring 8| of relay 86 and also charges another condenser 19 through leaf contacts 8|A and 82A. When ball 35 is released by the movement of carriage 36, the contacts 16 and Condenser 18 then discharges through the winding of relay 86 which operates and electrically locks up by current coming to the winding through holding contacts 8| and 82.- The operation of relay 86 connects a source of power through a voltage limit resistor L and through its contacts 83 and 64 to magnet 85. Magnet 85 operates armature 86 thereby moving a release bar 96 to the right. Release bar 96 is supported in position on pins 9| and Clutch member 4| is carried on shaft 46 coaxially arranged with 92, in inclined apertures 93. Thus as the bar 96 is moved to the right, it is also caused to rise, forcing pins 95 and 96 upwardly and disengaging pawls 58 and 66 from the racks 55 and 6|. A

spring (not shown) within spring drum I66 winds up carriage return cord I6 I, thus pulling the carriage 36 back to its rest position. As the carriage 36 reaches its extreme right hand position, the contacts 15 and 16 are separated by the action of pin |63 against contact 16, thus releasing relay 86. As relay 86 opens, condenser 19 discharges through contacts 8 IA. 83A and the winding of magnet ||6 causing vane l6 to rock backward and release the selected key in group I6.

The release slide 2 which cooperates with lever is adjustably mounted on carriage 36. Thus the moment of opening of contacts 13 and 14 may be adjusted. These contacts are connected in series in the signaling line S and a source of power P, as are also contacts 5| and 52 coacting with commutator 48.

What is claimed is:

1. A transmitter including means for generating equal length signaling impulses, a number of keys, one individual to each of a number of characters to be represented by different length trains of signaling impulses, means responsive to the selection of any one of said keys for initiating transmission of said impulses, means automatically disabling said generating means when the number of impulses transmitted is representative of the character represented by the selected key, and means responsive to the operation of said disabling means for restoring said disabling means to a position of rest. 1

2. A transmitter including means for generating equal length signaling impulses, a number of keys one individual to each of a number of characters to be represented by different length trains of signaling impulses, means responsive to the selection of any one of said keys for initiating transmission of said impulses, means automatically disabling said generating means when the number of impulses transmitted is representative of the character represented by the selected key, means responsive to the operation of said disabling means for releasing said disabling means for return to a position of rest, and further means for restoring the selected one of said keys.

3. A telegraph transmitter including a number of keys, one individual to each of a number of 7 characters, means for looking a selected key in Relay 86 is unoperated.

an'operated position, a commutator adapted to generate equal length signal impulses, a continuously rotating shaft, 'means responsive to the operation of any one of said keys for clutching said commutator to said shaft, means responsive to the operation of said one of said keys for disengaging said clutch upon generation of the number of impulses representative of the character associated with said operated key, means for restoring said disengaging means to a position of rest, and means responsive to said last mentioned means for releasing said locking means.

4. A telegraph transmitter including a number of keys, one individual to each of a number of characters, means for locking a selected key in an operated position, a commutator adapted to generate equal length signal impulses, a continuously rotating shaft, means responsive to the operation of any one of said keys for clutching said commutator to said shaft, an eccentric adapted to revolve with said commutator, a ratchet rack arranged to be reciprocated by said eccentric, a

of keys one individual to each of a number of characters, means for looking a selected key in an operated position, a commutator adapted to" generate equal length signal impulses, a continuously rotating shaft, means responsive to the operation of any one of said keys for clutching-v said commutator to said shaft, an eccentric adapted to revolve with said commutator a ratch' et rack arranged to be reciprocated by said eccentric, a carriage mounted to move along said rack one step in said rack for each reciprocation" thereof, a number of key levers each having a notch therein, normally all in alignment over the path of said carriage, the selector of any one of said keys acting to displace the notch in one of said key levers into the path of said carriage, said carriage carrying a cam surface adapt f,

ed to lift said key lever, means responsive to the lift of any of said key levers for disabling said clutching means, and means for returning safid carriage to a position of rest. i

6. A telegraph transmitter including a num of keys ,one individual to each of a number characters, means for looking a selected key-in an operated position, a commutator adaptedi to generate equal length signal impulses, a contin uously rotating shaft, means responsive to the operation of any one of said keys for clutching said commutator to said shaft, an eccentric adapted to revolve with said commutator a ratchet rack arranged to be reciprocated by said "eccentric, a carriage mounted to move along said rack one step in said rack for each reciprocation thereof, a number of key levers each having a notch therein, normally all in alignment over the path of said carriage, the selector of any one of said keys acting to displace the notch inipne of said key levers into the path of said carriage, said carriage carrying a cam surface adapte'dto lift said key lever, means responsive to theglift of any of said key levers for disabling said clutching means, means for returning said carriage to a position of rest, and a pair of contacts ad to be connected in series in a signaling line -and adapted to be opened by the return of saidcarriage to said position of rest.

ber

'1. A telegraph transmitter including means for generating equal length signaling impulses, a number of keys, one individual to each of a number of characters to be represented by different length trains of signaling impulses, means responsive to the selection of any one of said keys for initiating transmission of said impulses, a continuously rotating shaft, a commutator adapted to generate said different length trains of signaling impulses, means responsive to the operation of any one of said keys for clutching said commutator to said shaft, an eccentric adapted to revolve with said commutator, means for counting the number of impulses transmitted including a ratchet rack arranged to be reciprocated by said eccentric, a carriage mounted to move along said rack, .one step in said rack for each reciprocation thereof, means for disabling said generating means when the number of impulses transmitted is representative of the character represented by the selected keys, means responsive to the operation of said disabling means 8. A device for transmitting intelligence expressing the individual characters thereof in terms of varying numbers of equal length signal elements including an output circuit, a generator arranged to produce a continuous train of signal elements to be applied to said output circuit, a member arranged to be moved step by step in synchronism with theproduction of signal elements by said generator, a number of stops, one individual to each of a number of characters to be represented by different length trains of said signal elements, means responsive to the operation of any one of said stops to initiate movement of said member and to connect said. generator to said output circuit, and further means responsive to cooperation between said member and said one stop to disconnect said generator from said output circuit and restore said member to its initial position.

JAMES A. SPENCER. LEONHARD F. REINHOLD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 374,390 Bixley Dec. 6, 1887 1,142,68'1 Etienne; June 8, 1915 1,585,441 Vaughan May 18, 1926 2,412,625 Mallina Dec. 17, 1946 

